Client Setup No Longer Contacting EMS

[COA_11458]

I was tasked with leading a POC for the FortiEMS system to help manage our VPN already in place. A senior teammate set up the server months prior before I took this project and passed it off to me. I grabbed a clean install of Windows machine that is not on the domain and used that one to test on. The first install worked great, registered itself, and stayed online. Wanting to become proficient with the EMS server, I unregistered the device, deleted it from the EMS server, and then uninstalled it from the test machine. I recreated a new invite and now it refuses to connect.  

I am looking for any FAQ or suggestions on how to troubleshoot this issue. Did I go about this incorrectly?

[ebilcari · Accepted solution]

Make sure that the test machine can reach the EMS server on port 8013, also when it's not connected to a VPN.

[COA_11458]

Thank you.  Your suggestion led me to check everything that listens on port 8013.  That led me to realize that the invite was sending people to the IP, not the DNS name, and that is just not how we manage things here.  I changed the invite to the hostname, and now I am connected.  So, thank you, and that led me to the answer.  Thanks.